Steam reforming device

ABSTRACT

A steam reforming valve device comprising a casing structure having a steam inlet and outlet and further having steam consecutive passageways between the steam inlet and outlet, pressure reducing valve means provided within the steam passageways in the upstream part thereof, and temperature reducing means provided within the steam passageways in the downstream part thereof and as a separate structure from the pressure reducing valve means. The pressure reducing valve means and the temperature reducing means, while being assembled unitarilly with and within the casing structure, are mutually separated by a suitable distance. The constituent parts of the pressure reducing valve means can be replaced individually and independently of other parts.

United States Patent 1191 Onoda et al. Sept. 9, 1975 [54] STEAM REFORMING DEVICE 3,220,708 11/1965 Matsui 261/D1G. 13 x 75 Inventors: Toshiaki Onoda, Yokohama; FOREIGN PATENTS OR APPLICATIONS Smklcl Kubma Matsudo, both of 1,046,238 12 1953 France 261/118 [30] Foreign Application Priority Data July 31, 1972 Japan 47-76661 [52] US. Cl 261/64 R; 261/76; 261/118; 26l/D1G. 13 [51] Int. Cl Blf 3/04 [58] Field of Search 26l/DIG. 13, 118, 76, 64 R [56] References Cited UNITED STATES PATENTS 1,894,391 1/1933 Barrett et al 26l/DlG. 13 X 2,355,458 8/1944 Mastenbrook 26l/DIG. 13 X 2,717,637 9/1955 Huber 261/76 X 2,725,221 1l/1955 Pontow 261/64 R X 3,134,827 /1964 Pontow et al... 26l/DlG. 13 X 3,207,492 9/1965 Zikesch 261/118 X 3,219,325 ll/l965 Brown 26l/DlG. 13 X Japan Assignee: Tokico Ltd., Kawasaki, Japan Filed: July 30, 1973 Appl. No.: 383,515

Primary Examiner-Frank W. Lutter Assistant ExaminerWilliam Cuchlinski, Jr. Attorney, Agent, or FirmWaters, Schwartz & Nissen l 5 ABSTRACT A steam reforming valve device comprising a casing structure having a steam inlet and outlet and further having steam consecutive passageways between the steam inlet and outlet, pressure reducing valve means provided within the steam passageways in the upstream part thereof, and temperature reducing means provided within the steam passageways in the downstream part thereof and as a separate structure from the pressure reducing valve means. The pressure reducing valve means and the temperature reducing means, while being assembled unitarilly with and within the casing structure, are mutually separated by a suitable distance. The constituent parts of the pressure reducing valve means can be replaced individually and independently of other parts.

8 Claims, 2 Drawing Figures i l 19 13 Fi l a ob 20 $1 370 PATENTEDSEP M SHEET 2 BF 2 STEAM REFORMING DEVICE BACKGROUND OF THE INVENTION "This invention relates to a steam reforming valve device and more particularly to a device for converting steam at high temperature and high pressure into steam at low temperature and low pressure.

Heretofore, as means for converting superheated steam at high temperature and high pressure into lowtemperature, low-pressure steam, a device comprising, within a steam flowpath, a pressure reducing device disposed at an upstream position and a temperature reducing device disposed apart and downstream from the pressure reducing device. However, since the pressure reducing device and the temperature reducing device are respectively provided separately and, moreover, at separated positions in this known device, the space required for the installation of these devices is large, and a largenumber of accessory equipment items are required, whereby high costs are entailed. A further drawback is that, since the pressure reducing action and the temperature reducing actions with respect to the steam are carried out at relatively separated places, accurate control of both actions is difficult.

In endeavoring to overcome the above described drawbacks of the known device, a steam reforming valve wherein a pressure reducing valve and a temperature reducing means are integrated into a single unit has been proposed. In this proposed steam reforming valve, the pressure reducing valve part is provided with one or more cooling water injection nozzles for temperature reduction, and pressure reduction and temperature reduction are carried out with the same part and at' the same time.

In general, the wear rate of the valve body and the valve seat of a pressure reducing valve is high. Consequently, the serviceable life of these parts is short, whereby it is necessary to replace these parts after a certain short period of use. Furthermore, since the above described steam reforming valve proposed heretofore has a construction wherein the openings of water injection nozzles are formed in the valve seat part, replacement of the valve seat could not be carried out easily, whereby it was necessary to change the whole steam reforming valve.

Another problem arises from the direct contacting of water for cooling to the valve plug and valve seat which are being exposed to high-temperature steam, whereby so-called thermal cracks or fracturing due to thermal stress in the valve parts occur. As a result of this damage, also, the serviceable life of the valve is further shortened.

SUMMARY OF THE INVENTION Accordingly, it is a general object of the present in vention to provide a novel and useful steam reforming device wherein the above described difficulties heretofore encountered in the art are overcome.

More particularly, an object of the invention is to provide a steam reforming device which is integrally constructed as a single device yet has a temperature re ducing part which is provided in a position spaced apart by a suitable distance from a pressure reducing valve. In the device according to the invention, parts such as the valve body'and the valve seat can be changed or re placed irrespectively of the temperature reducing part.

Furthermore, since the water for cooling does not directly contact valve parts such as the pressure reducing valve, there is little possibility of shortening of the valve life.

Another object of the invention is to provide a steam reforming valve in which, by providing a stepped configuration in a Water injection orifice part, the steam flow past this part is effectively utilized to attain effective injection of cooling water in the form a fine spray into a temperature reducing section.

Other objects and further features of the invention will be apparent from the following detailed description with respect to a preferred embodiment of the invention when read in conjunction with the accompanying drawings, in which like parts are designated by like reference numerals.

BRIEF DESCRIPTION OF THE DRAWING In the drawing:

FIG. 1 is side view, in longitudinal section, of one embodiment of a steam reforming device according to the present invention; and

FIG. 2 is an'enlarged side view, in longitudinal section, of one important part of the steam reforming valve illustrated in FIG. 1.

DETAILED DESCRIPTION Referring to FIGS. 1 and 2, the steam reforming de vice shown therein has a device casing structure 10 having a steam passageway 10a provided with a steam inlet ll 1 for introducing superheated steam at high temperature and high pressure from a lateral direction and steam passageways 10b and extending in a direction perpendicular to the steam flowpath 10a. The passageway 10c is coaxially and contiguously connected to the passageway 10b and has a steam outlet 12 for conducting out steam which has been reformed, i.e., re duced in temperature and pressure, as described hereinafter. Between the passageways 10a and 10b, there is provided a chamber 13.

A sleeve-like cage l4 passing through the chamber 13 is tightly fitted in a hollow cavity 18 of the valve casing structure 10 and, in its part passing through the chamber 13, has through holes 15. Below the cage 14, a seat ring 16 consituting a valve seat is inserted into the casing structure 10 over a gasket 17 interposed therebetween. The axial centerline of the cage 14 coincides with the axial centerline of the steam passageways 10b and 100.

Within the cage 14, there is inserted a valve plug 19 in a fluid-proof manner and in a manner to slide freely in the axial direction. At the lower end of the valve plug 19, there is formed integrally and coaxially therewith a valve body 20 adapted to seat against and separate from the abovementioned seat ring 16. A valve stem 21 is fixed coaxially to the upper part of the valve plug 19 and extends upward and out of the valve casing structure to an upper stem end 21a, which is coupled to an actuating device (not shown) such as a diaphragm actuator.

A cover structure 22 is fixedly but detachably secured to the upper part of the valve casing structure 10 over a gasket 25 interposed therebetween by stud bolts 23 and nuts 24. When the cover structure 22 is thus secured in place, it presses down on the upper end of the cage 14., whereby the lower end of the cage 14 presses the seat ring 16 down on the gasket 17.

The cover structure 22 has a hollow interior, through which the above mentioned valve stem 21 is passed. A stem guide 26 for slidably guiding the valve stem 21 is fixed to the cover structure 22 near the lower part thereof. The cover structure 22 is further provided at its upper part with a sealing device comprising a packing retaining ring 27, a packing 28, a lantern ring 29, a packing ring 31, a retaining disk 32 for retaining the retaining ring 31, stud bolts 33 and nuts 34 for securing the retaining disk 32 to the cover structure 22, a lubricator plug 35 for lubricating the lantern ring 29, and other parts. The valve stem 21 passes through this sealing device.

In a part of the casing structure 10 contiguous to the steam passageway 10b, there is formed a recess 36, in which an orifice forming member 37 of cylindrical shape is inserted and fixed by a locking member 38. The orifice forming member 37, in this particular embodiment, comprises two orifice forming half members 37a and 37b, which upon being assembled form the stem passageway 10c. A clearance C 1 is provided be tween the upper surface of the orifice forming member 37 and the upper wall surface of the recess 36 in the casing structure 10. Furthermore, the area of the member 37 in contact of with the total wall surface of the recess 36 is designed to be a minimum.

Between the orifice forming half members 370 and 3712, an annular hollow space 39 is formed, and an annular sleeve 40 of thin wall thickness is inserted in this hollow space 39. A slit is provided in sleeve 40 corresponding to a slit (orifice) 41 between the orifice forming half members 37a and 3712. Accordingly, the internal space of the sleeve 40 is communicative by way of the slit of the sleeve 40 and the slit 4] with the passageway 100. The gap between the slit 41 and the seat ring 16 is selected in the instant embodiment to be approximately lmm. Concavities and convexities are formed on the outer surface of the sleeve 40. A clearance C is provided between the sleeve 40 and the orifice forming half members 370 and 37b thereby to reduce to a minimum the area of contact with these parts.

The inner diameter of the nozzle forming half mem ber 37b is made slightly greater than the inner diameter of the orifice forming half member 37a. Consequently, in the part of the slit 41, a stepped part (I (for example, of the order of 1mm.) is formed between the inner wall surfaces of the half member 37a and the half member 3712.

A water supply pipe 42 is passed transversely through the casing structure to communicate at its inner end with the interior of the sleeve 40. In outer end of this pipe 42 is provided with a fitting 43 through which water for temperature reduction is supplied to flow in the arrow direction B through the pipe 42 and into the interior of the sleeve 40. The water supply pipe 42 is held by a pipe holding structure 44, which is supported by the casing structure 10 but is also adapted to contact this structure with minimum contact area. Furthermore, a clearance C is provided also between the water supply pipe 42 and the casing structure 10.

As mentioned above, the area of contact between the orifice forming half members 37a and 37b, the area of contact between the sleeve 40 and the orifice forming half members 370 and 3712, the area of contact between the water supply pipe 43 and the casing structure 10, and the area of contact between the pipe holding structure 44 and the casing structure 10 are made as minimal as possible. For this reason, it is possible to maintain a great temperature different between the water for temperature reduction, which passes through the sleeve 40 and is ejected as a fine spray through the slit 41 as described hereinafter, and superheated steam at high tempeature to be reduced in temperature.

To the lower end of the casing structure 10, there is fixedly connected a reducer 45 having an interior communicating coaxially with steam outlet 12 and diverging with an inner diameter increasing with distance from the outlet 12. A perforated plate 46 provided with a large number of holes 47 is fixed to the downstream end of the reducer 45.

The steam reforming device of the above described structural organization according to the invention operates as follows.

Primary-side superheated steam at a high temperature of, for example, from 400 to 530C, and a high pressure of, for example, from 40 to kg/cm is supplied from a superheated steam source (not shown) and enters the steam reforming device through the inlet 11 to enter the passageway 10a and flow in the arrow direction A to the chamber 13.

Then, when the valve stem 21 is pulled upward, as viewed in the drawing, by the aforementioned actuating device activated by some means or a control signal, the valve plug 19 also is lifted unitarily with the stem 21, and the valve body 20 separates from the seat ring 16. Consequently, the primary-side steam which has entered the chamber 13 from the passageway 10a flows through the through holes 15 and between the valve body 20 and the seat ring 16 and, being here throttled and reduced in pressure to a pressure of from 2 to 40 kg/cmfl for example. flows at high velocity into the passageway 1017. Therefore, in the pressure reducing part formed by the valve body 20 and the seat ring 16, only pressure reduction of the primary-side steam is carried out.

The pressure reduced steam which has flowed into the passageway 10b flows further at high velocity into the passageway 10c. Here, the inner diameter of the orifice half member 370 has been made smaller than that of the orifice half member 37b, whereby, in the orifice member 37, the orifice half member 37a forms a kind of Venturi tube construction or throat. As a consequence, the water within the sleeve 40 is sucked through the slit (orifice) 41 formed between the orifice half members 37a and 37b by the negative pressure produced by the steam flowing from the passageway 10b to the passageway 10c and past this Venturi throat at high velocity. The water is thus ejected as a fine spray by the resulting atomization action.

The above mentioned pressure reduced stream is mixed with the fine spray of water ejected through the slit (orifice) 41 and thereby reduced in temperature as it flows through the interior of the reducer 45 in the arrow direction C. This steam is further agitated in a positive manner by the perforated plate 46 and thereby uniformly reduced in temperature to from to 300C, for example.

In this manner, secondary-side steam at low pressure and low temperature which has been uniformly reduced in pressure and temperature to specific values is obtained on the downstream side of the perforated plate 46 after it has passed through the holes 47 thereof.

In the operation of this steam reforming device, while pressure reduction of the steam is accomplished to a slight extent in the perforated plate 46, the greater part thereof is carried out in the aforementioned pressure reduction part formed by the valve body 20 and the seat ring 16. On the other hand, the steam temperature reduction is effectively carried out between the temperature reduction part including the slit 41 and the perforated plate 46.

In the case where this steam reforming valve is used in an automatic apparatus or device, pressure detecting means and temperature detecting means are installed downstream from the perforated plate 46 at positions near the downstream side thereof. Then, in accordance with the detection outputs of these detecting or monitoring means, the axial displacement of the stem 21 and the flowrate of the water supplied through the water supply inlet fitting 43 and into the sleeve 40 are automatically controlled.

When it becomes necessary tp replace a constituent part of the pressure reducing section of this device, such as the seat ring 16, this can be accomplished easily, unrelatedly to the temperature reduction section, by loosening and removing the nuts 24, lifting the cover structure 22 off the casing structure 10, and lifting out cage 14.

Further, this invention is not limited to these embodiments but various variations and modifications may be made without departing from the scope and spirit of the invention.

We claim:

1. A steam reforming device comprising: a casing structure having a steam inlet, a steam outlet and consecutive passageways therebetween; pressure reducing valve means in an intermediate part of said steam passageways and operating to reduce the pressure of superheated steam flowing at high temperature and high pressure into said passageways through said steam inlet to a predetermined pressure value; and temperature reducing means within the steam passageways downstream from said pressure reducing valve means and constituted as a separate structure therefrom and oper ating to discharge water as a spray into the hightemperature, low-pressure steam thus reduced in pressure by the pressure reducing valve means and thereby to reduce the temperature of this steam to a predetermined temperature value, said temperature reducing means comprising an orifice-forming member forming said passageway through which the steam reduced in pressure by said pressure reducing valve means flows and, moreover, forming an annular hollow space and an annular orifice of slit-form in the wall surface of the orifice-forming member, a hollow sleeve disposed within said annular hollow space in the orifice-forming member and having a slit communicating with said orifice, said sleeve having an outer perpheral shape conforming to said annular hollow space and being supported all around the periphery therein and projection and groove means between said sleeve and said annular hollow space for minimizing the area of contact therebetween and for maintaining temperature differential therebetween, and a water supply pipe extending through said casing structure into communication with the interior of the sleeve, said orifice and said passageway being so constructed that the flow of the steam through the passageway causes water to be ejected as a spray through the orifice and into the passageway.

2. A steam reforming device according to claim 1 further comprising a cover structure detachably fixed to the casing structure and covering said pressure reducing valve means inserted in the casing structure, such that constituent parts of the pressure reducing valve means can be disassembled and taken out of the casing structure for replacement by detaching the covering structure.

3. A steam reforming device according to claim 1 in which said orifice-forming member is so formed that, with the position of said orifice as a reference line, the inner diameter of the passageway upstream of said reference line is small, and that downstream of said reference line is large, whereby said passageway has a stepped configuration at said orifice.

4. A steam reforming device according to claim 3 wherein said stepped configuration of said passageway provides a Venturi throat serving for introduction of the water as a spray into said passageway.

5. A steam reforming device according to claim 1 in which said orifice-forming member comprises two orifice forming half members forming therebetween said orifice, the orifice forming half member upstream of the orifice having a smaller inner diameter than the other orifice forming half member downstream of the orifice.

6. A steam reforming device according to claim 1 in which clearances are provided respectively between the orifice forming member and the casing structure, between the sleeve and the orifice forming member, and between the water supply pipe and the casing structure.

7. A steam reforming device according to claim 1 which further comprises an exit passageway for conducting steam fiowing out of said steam outlet, and perforated plate means installed within said exit passageway, said perforated plate means having a large number of holes for passage therethrough of steam already sprayed with water.

8. A steam reforming device according to claim 1, wherein said projection and groove means comprises convexities and concavities on the periphery of said sleeve. 

1. A STEAM REFORMING DEVICE COMPRISING: A CASING STRUCTURE HAVING A STEAM INLET, A STEAM OUTLET AND CONSECUTIVE PASSAGEWAYS THEREBETWEEN, PRESSURE REDUCING VALVE MEANS IN AN INTERMEDIATE PART OF SAID STEAM PASSAGEWAYS AND OPERATING TO REDUCE THE PRESSURE OF SUPERHEATED STEAM FLOWING AT HIGH TEMPERATURE AND HIGH PREESURE INTO SAID PASSAGEWAYS THROUG SAID STEAM INLET TO A PREDETERMINED PRESSURE VALUE, AND TEMPERATURE REDUCING MEANS WITHIN THE STEAM PASSAGEWAYS DOWNSTEAM FROM SAID PRESSURE REDUCING VALVE MEANS AND CONSTITUTED AS A SEPARATE STRUCTURE THEREFROM AND OPERATING TO DISCHARGE WATER AS A SPRAY INTO THE HIGH-TEMPERATURE, LOW-PRESSURE STEAM THUS REDUCED IN PRESSURE BY THE PRESSURE REDUCING VALVE MEANS AND THEREBY TO REDUCE THE TEMPERATURE OF THIS STEAM TO A PREDETERMINED TEMPERATURE VALUE, SAID TEMPERATURE REDUCING MEANS COMPRISING AN ORIFICE-FORMING MEMBER FORMING SAID PASSAGEWAY THROUGH WHICH THE STEAM REDUCED IN PRESSURE BY SAID PRESSURE REDUCING VALVE MEANS FLOWS AND, MOREOVER, FORMING AN ANNULAR HOLLOW SPACE AND AN ANNULAR ORIFICE OF SLIT-FORM IN THE WALL SURFACE OF THE ORIFICE-FORMING MEMBER, A HOLLOW SLEEVE DISPOSED WITHIN SAID ANNULAR HOLLOW SPACE IN THE ORIFICE-FORMING MEMBER AND HAVING A SLIT COMMUNICATING WITH SAID ORIFICE, SAID SLEEVE HAVING AN OUTER PERPHERAL SHAPE CONFORMING TO SAID ANNULAR HOLLOW SPACE AND BEING SUPPORTED ALL AROUND THE PERIPHERY THEREIN AND PROJECTION AND GROOVE MEANS BETWEEN SAID SLEEVE AND SAID ANNULAR HOLLOW SPACE FOR MINIZING THE AREA OF CONTACT THEREBETWEEN AND FOR MAINTAINING TEMPERATURE DIFFERENTIAL THEREBETWEEN AND A WATER SUPPLY PIPE EXTENDING THROUGH SAID CASING STRUTURE INTO COMMUNICATION WITH THE INTERIOR OF THE SLEEVE, SAID ORIFICE AND SAID PASSAGEWAY BEING SO CONSTRUCTED THAT THE FLOW OF THE STREAM THROUGH THE PASSAGEWAY CAUSES WATER TO BE EJECTED AS A SPRAY THROUGH THE ORIFICE AND INTO THE PASSAGEWAY.
 2. A steam reforming device according to claim 1 further comprising a cover structure detachably fixed to the casing structure and covering said pressure reducing valve means inserted in the casing structure, such that constituent parts of the pressure reducing valve means can be disassembled and taken out of the casing structure for replacement by detaching the covering structure.
 3. A steam reforming device according to claim 1 in which said orifice-forming member is so formed that, with the position of said orifice as a reference line, the inner diameter of the passageway upstream of said reference line is small, and that downstream of said reference line is large, whereby said passageway has a stepped configuration at said orifice.
 4. A steam reforming device according to claim 3 wherein said stepped configuration of said passageway provides a Venturi throat serving for introduction of the water as a spray into said passageway.
 5. A steam reforming device according to claim 1 in which said orifice-forming member comprises two orifice forming half members forming therebetween said orifice, the orifice forming half member upstream of the orifice having a smaller inner diameter than the other orifice forming half member downstream of the orifice.
 6. A steam reforming device according to claim 1 in which clearances are provided respectively between the orifice forming member and the casing structure, between the sleeve and the orifice forming member, and between the water supply pipe and the casing structure.
 7. A steam reforming device according to claim 1 which further comprises an exit passageway for conducting steam flowing out of said steam outlet, and perforated plate means installed within said exit passageway, said perforated plate means having a large number of holes for passage therethrough of steam already sprayed with water.
 8. A steam reforming device according to claim 1, wherein said projection and groove means comprises convexities and concavities on the periphery of said sleeve. 